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Vulnerability record · CVE-2009-2505 · published 9 December 2009

CVE-2009-2505: Microsoft windows server 2008 improper authentication vulnerability

Microsoft · Windows Server 2008

The Internet Authentication Service (IAS) in Microsoft Windows Vista SP2 and Server 2008 SP2 does not properly validate MS-CHAP v2 Protected Extensible Authentication Protocol (PEAP) authentication requests, which allows remote attackers to execute arbitrary code via crafted structures in a malformed request, aka "Internet Authentication Service Memory Corruption Vulnerability."

10.0 CVSS 2.0 High EPSS 32% · top 1.8% CWE-287 · Improper authentication
10.0CVSS 2.0 base score
32%EPSS exploitation probability, 30 days
NoNot in CISA KEV
2Affected product versions listed by NVD
8References
16 Jun 2026Last modified by NVD

Description

The Internet Authentication Service (IAS) in Microsoft Windows Vista SP2 and Server 2008 SP2 does not properly validate MS-CHAP v2 Protected Extensible Authentication Protocol (PEAP) authentication requests, which allows remote attackers to execute arbitrary code via crafted structures in a malformed request, aka "Internet Authentication Service Memory Corruption Vulnerability."

AV:N/AC:L/Au:N/C:C/I:C/A:C

Affected products

2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://www.securitytracker.com/id?1023291
http://www.us-cert.gov/cas/techalerts/TA09-342A.html US Government Resource
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2009/ms09-071
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A6063
http://www.securitytracker.com/id?1023291
http://www.us-cert.gov/cas/techalerts/TA09-342A.html US Government Resource
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2009/ms09-071
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A6063

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2009-2505), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.